An electro-optic Q-switched Nd：YAG ceramic laser operating at kHz repetition rate was demonstrated. Thermal induced lens＇ focus of ceramic rod was measured and compensated by piano-convex cavity structure. Depolariz...An electro-optic Q-switched Nd：YAG ceramic laser operating at kHz repetition rate was demonstrated. Thermal induced lens＇ focus of ceramic rod was measured and compensated by piano-convex cavity structure. Depolarization loss at different output powers was measured in Nd：YAG single crystal and ceramic lasers. High-energy high-beam-quality laser pulse output was obtained in both laser structures. Pulse energy of about 20 mJ and pulse width of less than 12 ns were achieved, and the average power reached 20 W. The divergence of output laser beam was less than 1.2 mrad, and the beam propagation factor M^2 was about 1.4.展开更多
Scattering noises in four kinds of lithium niobate crystals with the same double doping system, which are LiNbO3:Fe:Mn, LiNbO3:Ce:Mn, LiNbO3:Ce:Cu, and LiNbO3:Fe:Cu, are observed and compared experimentally. The resul...Scattering noises in four kinds of lithium niobate crystals with the same double doping system, which are LiNbO3:Fe:Mn, LiNbO3:Ce:Mn, LiNbO3:Ce:Cu, and LiNbO3:Fe:Cu, are observed and compared experimentally. The results show that nonvolatile holographic recording can effectively suppress scattering noise, which mainly depends on recombination coefficients of both the shallower centers and the deeper centers. The small recombination coefficients of the shallower centers and the large recombination coefficients of the deeper centers benefit the amplification of the signal gratings and the suppression of the noise gratings. In addition, the initial seed scattering also impacts the recorded scattering noise, and the little seed scattering results in low scattering noise. The theoretical simulations are performed for confirmation. Among the four kinds of doubly doped crystals, in LiNbO3:Ce:Cu the performances of nonvolatile recording are the best with low scattering noise and high diffraction efficiency.展开更多
Based on the theory of semiconductor laser pattern and the non-paraxial vectorial moment theory of light beam propagation, the beam quality factor M2 of TE0 propagating mode is analyzed and calculated. The result show...Based on the theory of semiconductor laser pattern and the non-paraxial vectorial moment theory of light beam propagation, the beam quality factor M2 of TE0 propagating mode is analyzed and calculated. The result shows that when both core layer and cladding layer are considered, M2>1 is always obtained. Moreover, by analyzing the characteristic of real beams, this result is generalized to the multilayer isotropic linear slab waveguide.展开更多
文摘An electro-optic Q-switched Nd：YAG ceramic laser operating at kHz repetition rate was demonstrated. Thermal induced lens＇ focus of ceramic rod was measured and compensated by piano-convex cavity structure. Depolarization loss at different output powers was measured in Nd：YAG single crystal and ceramic lasers. High-energy high-beam-quality laser pulse output was obtained in both laser structures. Pulse energy of about 20 mJ and pulse width of less than 12 ns were achieved, and the average power reached 20 W. The divergence of output laser beam was less than 1.2 mrad, and the beam propagation factor M^2 was about 1.4.
文摘Scattering noises in four kinds of lithium niobate crystals with the same double doping system, which are LiNbO3:Fe:Mn, LiNbO3:Ce:Mn, LiNbO3:Ce:Cu, and LiNbO3:Fe:Cu, are observed and compared experimentally. The results show that nonvolatile holographic recording can effectively suppress scattering noise, which mainly depends on recombination coefficients of both the shallower centers and the deeper centers. The small recombination coefficients of the shallower centers and the large recombination coefficients of the deeper centers benefit the amplification of the signal gratings and the suppression of the noise gratings. In addition, the initial seed scattering also impacts the recorded scattering noise, and the little seed scattering results in low scattering noise. The theoretical simulations are performed for confirmation. Among the four kinds of doubly doped crystals, in LiNbO3:Ce:Cu the performances of nonvolatile recording are the best with low scattering noise and high diffraction efficiency.
基金This work was supported by the Natural Science Foun-dation of Zhejiang Province under Grant No.601133.
文摘Based on the theory of semiconductor laser pattern and the non-paraxial vectorial moment theory of light beam propagation, the beam quality factor M2 of TE0 propagating mode is analyzed and calculated. The result shows that when both core layer and cladding layer are considered, M2>1 is always obtained. Moreover, by analyzing the characteristic of real beams, this result is generalized to the multilayer isotropic linear slab waveguide.
